HomeMy WebLinkAboutHORSETOOTH-TIMBERLINE PROPERTY - MASTER PLAN - 78-88 - SUBMITTAL DOCUMENTS - ROUND 1 - TRAFFIC STUDY00
m
g
MI
--;I
M
CD
N
M
CD
CO
co
O
co
CD
z
w
w
z
C7
z
w
J
CU
z
O_
H
H
O
a
CIO
11
U-
U-
cc
F-
MEHORAIADUM
To: Charles Deane, W.W. Reynolds Companies
City of Fort Collins Staff
From: Matt Delich �T
Date: September 28, 1988
Subject: Timberline—Horsetooth Property Traffic Study
I am submitting the traffic study as a. draft due to late
authorization to proceed with this work. The text is in
final form while the graphics are "mock ups" that will
be formalized in the next few days. The appendices will
be in the final report, which will be submitted during
the week of October 3, 1988. Thank you.
0
? I
)SITE ACCESS STUD*-(
PROPERTY
FORT COLLINS, COLORADO
SEPTEMBER 1988
Prepared for:
W. W. Reynolds Companies
1919 14th Street, Suite 802
P. O. Box 1666
Boulder, CO 80306
Prepared by:
MATTHEW J. DELlCH, P.E.
3413 Banyan Avenue
Loveland, Colorado 80538
Phone 303-669-2061
EXECUTIVE SUMMARY
Timberline-Horsetooth Property is a proposed development
located near the intersection of Horsetooth Road and
Timberline Road. This traffic impact study involved the
steps of trip generation, trip distribution, trip assignment,
capacity analysis, traffic signal warrant analysis, signal
progression analysis_., and accident analysis.
This study assessed the impacts of the Timberline-
Horsetooth Property on the short range (1992) and long range
(2010) street system in the vicinity of the proposed
development. As a result of this analysis., the following is
concluded:
- The development of the Timberline-Horsetooth Property
is feasible from a traffic engineering standpoint. At full
development as proposed, approximately 12,500 trip ends will
be generated at this site daily.
- The Horsetooth/Timberline intersection currently
operates acceptably with signal control and the existing
geometrics.
- By 1992, given the first phase of development of the
Timberline-Horsetooth Property; Phase 1 of Collindale
Business Park; Phases 1, 2, and 3 of Fox Meadows; and an
increase in background traffic, the signalized intersection
of Horsetooth/Timberline will operate acceptably with the
existing geometrics and left -turn signal phases. At this
level of development, Timberline Road and Horsetooth Road can
remain two lane streets with auxiliary lanes at the access to
Parcel A. Left -turn exits at the Horsetooth/Access
intersection will operate unacceptably during the afternoon
peak hour. There is little that can be done to improve this
operation. There will be left -turn storage conflicts between
the Timberline/Horsetooth intersection and the Horsetooth/
Access intersection.
- No new signals are warranted in the short range
future. With full development of the Timberline-Horsetooth
Property and other nearby properties, signals will likely be
warranted at the Timberline/Big Horn and the Horsetooth/
Access intersections.
- Signals at the Timberline/Caribou and Timberline/Big
Horn intersections will not negatively impact the signal
progression along Timberline Road. The signal at the
Horsetooth/Access intersection will not negatively impact the
signal progression along Horsetooth Road. This intersection
will function as a minor signalized intersection.
By 2010, the Horsetooth/Timberline intersection will
operate acceptably in the peak hours with geometric
improvements to both Horsetooth Road and Timberline Road.
The necessary geometrics are shown in Figure 10. With
signalization, the Horsetooth/Access and Timberline/Big Horn
intersections will operate acceptably. The proposed right-
in/right-out access to Timberline will operate acceptably.
It must be placed at a distance from Hor•setooth Road based
upon the design speed of Timberline Road. A right -turn
deceleration lane should be designed at this access. The
proposed right-in/right-out access from Horsetooth Road is
projected to have little effect on traffic generated at this
site. It will primarily serve as a convenience access to the
southern portion of the site. Consideration should be given
to eliminating this access in order to emphasize the main
access to Parcel A.
- With the recommended control and geome tr i cs, the
accident rate should be at an acceptable level for typical
urban conditions.
I. INTRODUCTION
This traffic impact study addresses the capacity,
geometric, and control requirements at and near a proposed
development known hereinafter as the Timberline-Horsetooth
Property. It is located near the intersection of Timberline
Road and Horsetooth Road in Fort Collins, Colorado.
During the course of the analysis, numerous contacts
were made with the developer MI. W. Reynolds Companies), the
planning consultant (Citxscape), and the Fort Collins Traffic
Engineering Department. This study generally conforms to the
format set forth in the Traffic Impact Study Guideline.. The
study involved the following steps:
- Collect physical, traffic and development data.
- Perform trip generation, trip distribution, and trip
assignment.
- Determine peak hour traffic volumes and daily traffic
volumes.
- Conduct capacity and operational level of service
analyses on key intersections and roadway sections.
- Analyze signal warrants and signal progression.
- Analyze potential changes in accidents and safety
considerations.
II. EXISTING CONDITIONS
The location of the Timberline-Horsetooth Property is
shown in Figure 1. It is important that a thorough
understanding of the existing conditions be presented.
Land Use
Land uses in the area are primarily vacant, agricultu-
ral, industrial, or recreational. Vacant land exists to the
south. This is the location of a proposed industrial park
known as Collindale Business Park. An agricultural use
exists to the northeast across Horsetooth/Timberline
intersection. The Collindale Golf Course is to the west of
the site across the Union Pacific Railroad tracks. North of
the site is the facility of the Platte River Power Authority.
To the east, across Timberline Road is farm property. This
property is the location of a proposed residential/commercial
development known as Fox Meadows. Land in the area is
essentially flat. The center of Fort Collins lies to the
north of the Timberline-Horsetooth Property.
1
f'
O#j
M aF Gt to
Swre LOC.A-TIO*',)
FIGuFE
0
•
Roads
The primary streets near the Timberline-Horsetooth
Property are Horsetooth Road and Timberline Road. Timberline
Road is east of the Timberline-Horsetooth Property. It is a
north -south street designated as a major arterial on the Fort
Collins Master Street Plan. In this area, it has a two lane
rural cross section with auxiliary turn lanes at Horsetooth
Road. The posted speed limit is 40 mph. Sight distance is
generally not a problem along Timberline Road. The
Horsetooth/Timberline intersection has signal control. The
nearest other signal along Timberline Road is at Prospect to
the north and Harmony to the south.
Horsetooth Road borders this site on the north. It is
an east -west street designated as an arterial on the Fort
Collins Master Street Plan. East of Timberline Road,
Horsetooth Road is built to a half urban street cross
section. West of Timberline Road, it is built to the full
urban arterial cross_. section. There are left -turn lanes at
the Horsetooth/Timberline intersection. The posted speed on
Horsetooth Road is 40 mph west of Timberline and 45 mph east
of Timberline.
Existing Traffic
Daily traffic flow is shown in Figure 2. These are
machine counted volumes conducted by the City of Fort Collins
in 1984. Peak hour turning movements obtained in June, 1988
are shown in Figure 3. Raw traffic count data is provided in
Appendix A.
Existing Operation
The Horsetooth/Timberline intersection, which was
counted in June 1988, was evaluated regarding operational
efficiency. It was evaluated using existing signal control
with existing geometrics and the volumes shown in Figure 3.
The peak hour operation is shown in Table 1. Calculation
forms are provided in Appendix B. Appendix C describes level
of service for signalized and unsignalized intersections from
the 1985 Highway Capacity Manual. With the existing control,
this intersection operates acceptably except that left -turns
do not always clear. This can be remedied by introducing a
left -turn phase on each approach. Even with the additional
time needed for the left -turn phase, acceptable operation is
achieved.
E
•
2) o I a(,
L956 (I°)83�
N
0
0
co
w
1541 ( I-) a3)
Zcc
J
w
HORSETO OTH
sM
Ir s
�o
M �
co
N
RECENT DAILY TRAFFIC COUNTS
w
J
w
m
_
oar
�
L
Ln
J I
8 41,/143
2/1
ICl/8a } HORSETOOTH
IZZ/ 67- —1, I
105/°fZ �\ N 0 �
� N �
O �
N
FIGURE 2
AM/PM
1988 PEAK HOUR TRAFFIC FIGURE 3
E
•
Table 1
Existing Peak Hour Operation
Intersection AM Peak Hour PM Peak Hour
Timberline/Horsetooth
Existing Geometric_/Phasing A t0.22) A f0.32?
Existing Geometr i c_/Heav i est A 40.37? A (0.42)
LT protected
Table 2
Trip Generation
Daily A.M. Peak: P.M. Peak
Lend Use Trip=. Trips Trips Trips Trips
in out in out
Phase 1 - Parcel A
Retail -
155.5 KSF
7720
Full Development
Parcel B
Office/Ind.-
100.0 KSF
?70
Parcel C
Commercial
- 31.75 KSF
1580
Parcel U
Commercial
- 25.0 KSF
1240
Parcel E
Office - 40.0
KSF
500
Parcel F
Office/Ind.
- 55.0 KSF
530
Total
12540
138
12?
82 403 412
125 116
28
17
82
84
22
1.j
"5
6
70
?
12
ti 5
71
10
14
64
458
14?
601
807
III. PROPOSED DEVELOPMENT
Timberline-Horsetooth Property is a proposed retail/
industrial/office park development located southwest of the
Horsetooth/Timberline intersection in Fort Collins. Figure 4
shows a schematic of the site plan of the Timberline-
Horsetooth Property indicating location of the uses shown in
Table 2, Trip Generation. The short range analysis (1992)
included Parcel A - Neighborhood Service Center indicated in
Table 2 as Phase 1. The plan for Phase 1 shot -is an access
from Timberline Road on the east and two accesses from
Horsetooth Road on the north. The proposed access near the
railroad tracks and the access from Timberline Road to Parcel
A are intended to be right-in/right out. The right-in/right-
out near the railroad tracks also serves as an access to the
southern portion of the site. This access would not have a
significant function in the development of Parcel A. The
long range analysis (2010) included full development of the
Timberline-Horsetooth Property development along with other
proposed/expected uses to the south and east of this site and
an increase in background traffic in general accordance with
the North Front Range Corridor Study.
Trip Generation
Trip generation is important in considering the impact
of a development such as this upon the existing and proposed
street system. A compilation of trip generation information
was prepared by the Institute of Transportation Engineers in
1976, updated in 1983, and was used to project trips that
would be generated by the proposed uses at this site. These
rates were supplemented using Development and Application of
Trip Generation Rates, FHWA, January 1985. Table 2 shows the
expected trip generation on a daily and peak hour basis. For
the office/light industrial use, a composite trip generation
factor was developed assuming a 50/50 split of these two
uses. The neighborhood service center and commercial uses
used shopping center trip generation factors. Based upon
analysis of the trip generation tables, the shopping center
use would cover the grocery store and other retail uses
intended for this site. No adjustments were made for transit
or ridesharing. Therefore, the trip generation can be
considered conservatively high.
Trip Distribution
Two directional distributions of the generated trips
were determined for the Timberline-Horsetooth Property.
Distributions from the intended uses used population as the
attraction variable in the gravity model. Future year data
were obtained from information supplied by the Fort Collins
3
0
0
Igo
SITE KAO
0
E
Planning Department. The trip distributions are shown in
Figure S.
Traffic Projections
Traffic projections for the short range time period
(1992) were obtained by factoring the existing traffic by 108
percent (27% per year) for Horsetooth Road and for Timberline
Road to obtain the expected traffic in 1992. Also included
in the traffic projections were developments to the east (Fox
Meadows) and to the south (Col1indala Business Park), which
were likely to be partially developed by 1992. This traffic
is identified as background traffic which passes by the site
on Timberline Road and Horsetooth Road. Figure 6 shows the
expected 1992 daily traffic considering the site generated
traffic and the background traffic.
For 20+ year projections (year 2010), the usual source
for projections is. the Traffic Flow Map as provided by the
City. However, the last Traffic Flow Map provides
projections for only the year 2000. The North Front Range
Corridor Study is also used as a reference. Therefore, an
estimation was made of traffic in this area by the year 2010
using the latest Traffic Flow Map, the North Front Range
Corridor Study, and the knowledge of what has been occurring
and what is expected to occur in this area. of Fort Collins.
These daily projections are shown in Figure 7. These volumes
assume that the system indicated on the Fort Collins Master
Street Plan is in place.
Trip Assignment
Trip assignment is how the generated and distributed
trips are expected to be loaded on the street system. The
assigned trips are the resultant of the trip distribution
process. Figure 8 shows the short range morning peak hour
assignment and the afternoon peak hour assignment of Phase 1
of the Timberline-Horsetooth Property generated traffic plus
background traffic. Figure 9 shows the long range peak hour
assignment of full development of the Timberline-Horsetooth
Property with background traffic, assuming implementation of
the road network indicated on the Fort Collins Master Street
Plan.
Si gnat Warrants
As a matter of policy, traffic signals are not installed
at any location unless warrants are met according to the
Manual on Uniform Traffic Control Devices. However, it is
possible to determine whether traffic signal warrants are
likely to be met based upon estimated ADT and peak hour
0
• 0
30� t s
30,
agA
�-
He Inc- TooT M
6
St1oRT ZANaC--//,p,0iG 40Gt
�iP D isTK1BUTio0
n
O
0
N
93on
No 2SE ToCT14
DAU-V TAFFIC
0 16
0
0
N'
M
Z�, o0o Z I' Q00
j�o25�TouT1{
S� Tt
J
0 W
0
N
LONG RANEE DAILY TAFFiC. FIr,ueE 7
U
pg ?A
p S/I
1615-3
-8/18�
f>ACCeL
A
A41PM
�
N
r N
�- go/Z 3`j
/57/142-
1-�4/1 $Z
M M
10
3t4.,,,e-r ZA,,KC PcAK HoOP. 7RAFFIC
more serooTrl
Flauge 8
0 0
9 �
O
\O
2 SO��Uo
I
Z 4)
�-- 8 gO�1440
�
(� m M
L
97(15/Z"s
�%
.�«_.....:.:,..gar....
Z2o/zoo
.�r..�.eru9:pa�ar.,-e,.....,.,_.,.,.,=`.—_.ae:
zes.=Yerms�er�..—+-+.:�� Y.w++w`=�,
14-15/9„--a s/� �'
._rt.r...�t-�s,...rww+n•u•sno+maa+maa-�-.e...,
°1 �(� 4001-Z o9D J
:�n.
`l 1 r' NorseTroTN
10135- Co0
9 0
�•
4.70/Z8O--'►
i6-& 016Z
9 O
ONO
N �
00
0
m
s�
3 s/<
A MIPM
W
2
J
0�
w
to
�l
F-
a
a
Im 70 /9 s'
$►ts Hoeg
v
�-
00
LONG �ANt.E PEAK Xuf— 7RAPFIC.
F%cur
0 i
signal warrants shown in Appendix D. Using the daily traffic
volumes, a signal is not warranted at the Horsetooth/Access
intersection. Using the peak hour traffic shown in Figure 8,
a signal is not warranted in the morning peak hour, but is
warranted in the afternoon peak hour. It is recommended that
a signal not be installed in the short range future.
Operation will be discussed later in this report.
Using the traffic volumes in Figures 7 and 9, a traffic
signal is likely to be warranted at the Timberline/Big Horn
and the Horsetooth/Access intersections. Big Horn Drive is
in the Fox Meadows development on the east side of Timberline
Road and in the Timberline-Horsetooth Property on the west
side of Timberline Road.
Signal Progression
Signal progression was evaluated prior to intersection
operational analysis in order to evaluate whether the
potentially warranted signals at the Timberline/Big Horn Road
and Horsetooth/Access intersections can fit into a signal
progression pattern along Timberline Road and Horsetooth
Road, respectively. Other signals along Timberline Road and
Horsetooth Road were inserted based upon judgment and
included signals which would yield a reasonable level of
analysis.
The technique used in the signal progression analysis
was a computer program called Signal Progression Analysis
(SPAN) prepared by the University of Florida Transportation
Research Center. Its main functions include:
- Interactive entry of arterial system data.
- Display a time location diagram which provides
graphical representation of the quality of arterial
progression.
- Printing of a time -space diagram to show the quality
of progression.
- Optimization of signal offsets for arterial pro-
gression.
The program inputs are:
- Intersection location
- Cycle length
- Phasing
- Offsets
- Speed
Any or all of these inputs can be changed iteratively in
achieving the optimal progression.
5
0
•
The signal progression on Timberline Road was analyzed
based upon the following criteria:
- Cycle length of 90-120 seconds.
- Posted speed of 35-40 mph.
- Mainline (Timberline) G/C Ratio
Drake G/C = 0.40
Collector G/C = 0.60
Collector G/C = 1.00 (no signal)
Horsetooth G/C = 0.40
Big Horn G/C = 1.00 (no signal), G/C = 0.75 (with
signal)
Caribou G/C = 1.00 (no signal), G/C = 0.60 (with
signal)
Harmony G/C = 0.40
- Green time on the cross street is greater than the
pedestrian crossing time of the mainline at 4 feet
per second.
- Achieve the largest bandwidth possible along Timber-
line Road.
A number of cycle lengths and speeds were examined.
Appendix E shows four progression analyses for Timberline
Road. Page 1 shows a time -space diagram using a 90 second
cycle and 40 mph with no signal at Big Horn Drive and Caribou
Drive. Bandwidths of 31 seconds (34% efficiency) are
achieved in each direction. Page 2 shores the same criteria
with signals introduced at Big Horn Drive and Caribou Drive.
The bandwidths are the same as those indicated on Page 1.
Page 3 shows a time -space diagram using a 100 second cycle
and 35 mph with no signals at Big Horn Drive and at Caribou
Drive. Bandwidths of 37 seconds (37;. efficiency) are
achieved in each direction. Page 4 shows the same criteria
with signals introduced at Big Horn Drive and Caribou Drive.
The bandwidths are the same as those indicated on Page 3. It
is concluded that signals at Big Horn Drive and Caribou Drive
will not negatively impact signal progression along
Timberline Road.
The signal progression on Horsetooth Road was analyzed
based upon the following criteria:
- Cycle length of 90-100 seconds (same as the selected
cycle lengths on Timberline)
- Posted speed of 35-40 mph.
- Mainline (Horsetooth) G/C Ratio
Parcel A Access. G/C = 0.70
Timberline G/C = 0.40
Arctic Fox G/C = 0.60
Caribou G/C = 0.60
Johnson Farm Collector G/C = 0.60
Additional Johnson Farm intersection G/C = 1.00
(no signal)
County Road 9 G/C = 0.50
6
Green time on the cross street is greater than the
pedestrian crossing time of the mainline at 4 feet
per second.
- Achieve the largest bandwidth possible along Horse -
tooth Road.
Pages 1-8 of Appendix F show time -space diagrams for
Horsetooth Road. Pages 1, 3, 5, and 7 show the signal pro-
gression without a signal at the Horsetooth/Access inter-
section. Pages 2, 40 6, and 8 show the signal progression
with a signal at the Horsetooth/Access intersection. The
bandwidths are the same for each matching set of speed and
cycle length criteria. It is concluded that a signal at the
Horsetooth/Access intersection will not negatively impact
signal progression along Horsetooth Road.
The Horsetooth/Access intersection is approximately 600
feet from Timberline. This is sometimes called a minor
signalized intersection. This concept was recommended in the
"Access Control Demonstration Project," prepared for the
Colorado Department of Highways, District 6. It has been a
method of providing access to corner properties located at
the intersections of major arterial streets. It has been
implemented in the City of Lakewood. The Lakewood Traffic
Engineering Department was contacted to gain some insight
with regard to their experience with this concept. The
following comments were made:
- The access point proposed for signalization must have
much lower traffic volumes when compared to the major street.
A "rule of thumb" ratio of greentime is 1/3 versus 2/3.
- The left -turn lane storage requirements on the major
street at the arterial/arterial intersection take precedence
over the location of a signal at the access.
- The access signal should have as few phases as.
possible. A two or three phase signal seems to work best. A
full eight phase signal is unacceptable.
- At the intersection of two arterials, it is
acceptable to introduce signals at the accesses on two legs,
but not on all four legs.
The minor signalized intersection concept has been
implemented in Lakewood on two adjacent legs at the
Wadsworth/Jewell intersection. Wadsworth Boulevard is a six
lane arterial which is also State Highway 121. Jewell Avenue
is a four lane arterial. The Lakewood Traffic Engineering
Department stated that these signals have been performing
satisfactorily, serving the adjacent land uses and not
negatively impacting either Wadsworth Boulevard or Jewell
Avenue. Based upon the preceeding progression analyses, the
operational and geometric analyses provided later in this
7
•
report, and the acceptability of this concept in the State of
Colorado, it is recommended that the minor signalized
intersection concept be considered at this location. Final
determination is subject to more refined "design level"
studies.
The above progression analyses are presented to shov.,
that the Horsetooth/Access and Timberline/Big Horn signals
can fit into a progression pattern along the respective
streets. Design progression analysis must be conducted on a
regular basis reflecting change in land use, speed, and other
variables.
Operations Analysis
Capacity analyses were performed on key intersections
adjacent to the Timberline-Horsetooth Property. The short
range analyses were performed on the Horsetooth/Timberline
and Horsetooth/Access intersections due to the proposed
phasing of this development. The long range analyses were
performed on all the key intersections.
Using the traffic volumes shown in Figure 8 and the
existing geometrics, the intersections operate in the short
range condition as indicated in Table 3. Calculation forms
for these analyses are provided in Appendix G. The
Horsetooth/Timberline intersection operates acceptably with
traffic signals. It is recommended that, at a minimum, left -
turn phases be provided for the heaviest movement north/south
and east/vlest. If the changes in traffic cannot be detected
by the available equipment, then fixed -time left -turn phases
will be necessary. This will be less efficient, but the
level of service will remain in acceptable categories. The
left -turn lanes should be: eastbound - 150-200 feet;
southbound - 100-130 feet; westbound - 70-90 feet; and
northbound - 150-200 feet at this level of development.
The stop sign controlled Horsetooth/Access intersection
will operate unacceptably during the afternoon peak hour.
Left -turn exits from this access will be in the level of
service E category. It is common that this movement will
fall into unacceptable operational levels prior to signals
being warranted. There is little that can be done to remedy
this. The delays to these left -turn movements will likely
occur for only a portion of the afternoon peak hour and
should be accepted. Provision of a left -turn lane on the
Access viill confine delays to only those vehicles desiring to
turn left. Left- and right -turn auxiliary lane• are required
at the Horsetooth/Access intersection. The right -turn
auxiliary lane should be 370 feet (including taper) given the
40 mph posted speed. The existing cross section on this
portion of Horsetooth Road accommodates five lanes. The
existing curb lane can possibly be used for this auxiliary
8
Table 3
Short Range Peak. Hour Operation
Intersection AM
Peak Hour
FM Peak:
Hour
Timberline/Horsetooth
Existing Geometries/Heaviest
A (0.51)
C: (0
• )
LT protected
Hor _.etooth Acce_•_•
EB LT
A
A
WB LT
A
A
S B LT
C:
E
SB RT/T
A
A
NB LT
C
E
NB RT/T
A
A
Timberline/Right-in/Right-out
EB RT
A
A
Table 4
Lang Range Peak Hour
Operation
Intersection AM
Peak Hour
PM Peak:
Hour
Timberl ine'Horsetooth
4 lane + LT & RT lanes on
C (0.76)
D (0.78)
Horse tooth/6 lane + SBLT lanes
+ 2 NBLT lanes + MINT lanes on
Timberline
Horsetooth/Acre_._.
A (0.49)
B (0.57)
Timberline/Big Horn
A (0.42)
B (0.58)
Timberline/Right-in/Right-out
EB RT
A
A
Hor _•etooth/Right-i n/R.i ght-out
NB RT
A
A
right -turn lane since the short range projection does not
indicate the need for two through lanes in each direction
from a capacity point of view. The left -turn lane
(westbound) into this access should be 370 feet (deceleration
and taper) plus 120 feet (storage), totalling 490 feet. This
is almost the full distance between Timberline and this
access. This westbound auxiliary lane would conflict with
the eastbound left -turn lane at the Horsetooth/Timberline
signalized intersection. Using the desirable length for the
eastbound left -turn lane (200 feet + taper), the longest
westbound left -turn lane at the access would be 180 feet.
Using the minimum length for the eastbound left -turn lane
(150 + taper), the longest westbound left -turn lane at the
access would be 230 feet.
A right-in/right-out access to Parcel A is proposed from
Timberline Road. Due to deceleration lane requirements (370
feet using the posted speed), this access should be
approximately 455 feet south of the south curbline of
Horsetooth Road. If this is physically not possible, the
design will need to be coordinated with the Fort Collins
Traffic Engineer. Not having the right-in/right-out access
to Timberline Road would require almost 20 percent of the
trips generated by Parcel A to utilize the main access at
Horsetooth Road. This will further increase the westbound
left -turn requirements (discussed earlier) at the
Horsetooth/Access intersection.
Under the short range future condition, Timberline Road
and Horsetooth Road require a two lane cross section with the
auxiliary lanes mentioned above. The above analyses and
recommendations also include development of Phases 1, 2, and
3 of the Fox Meadows development and Phase 1 of the
Collindale Business Park. Other development which may occur
in the area is reflected in the 2 percent per year increase
of the background (existing) traffic.
Using the traffic volumes shown in Figure 9, the key
intersections operate in the long range future as indicated
in Table 4. Calculation forms for these analyses are
provided in Appendix H. It is expected that by this future
date (2010), the Timberline-Horsetooth Property, as well as a
number of other parcels, will be at full development. In
order to attain acceptable operation during both peak hours
at the Horsetooth/Timberline intersection, it is recommended
that each approach be provided with the geometrics shown in
Figure 10. Even with these geometric improvement=_, the
operation of this intersection falls into marginal level of
service D in the afternoon peak hour. Since this will likely
occur for only a few cycles of the afternoon peak hour, it
should be accepted. The Timberline/Big Horn signalized
intersection will operate acceptably. The geometrics at this
intersection are also shown in Figure 10.
9
s
d
r
m
.9
d2g-a'-34o� i-TArea
N o R S E'TOOTH
i
's
8
i
IZ
d
I
a
e
N
,y
�-° BIG t4cu
FY
8
Ifr
LONG RAkIr,e Ge oM U TRICS
I-Ir, up,(' 10
0 •
The signalized Horsetooth/Access intersection will
operate acceptably. The recommended geometrics are shown in
Figure 10. The desirable left -turn lane requirements for the
Horsetooth/Access and Horsetooth/Timberline intersections
total 650 feet plus taper. This is in excess of the
available distance between these two intersections. The only
way to meet the geometric requirements is to provide a double
eastbound left -turn lane at the Horsetooth/Timberline
intersection. If the double eastbound left -turn lanes are
selected as an option, then the operation of the Horsetooth/
Timberline intersection will improve over that shown in Table
4.
As in the short range analysis, the proposed right-
in/right-out from Timberline Road will require a deceleration
lane based upon the posted speed of Timberline Road. At the
current 40 mph, a deceleration lane of 370 feet including
taper is required. Based upon design considerations on other
Fort Collins development projects, a design speed of less
than 40 mph should not be used. As stated in the short range
analysis, this access should be approximately 455 feet south
of the south curbline of Horsetooth Road.
A right-in/right-out access has been proposed from
Horsetooth Road just east of the railroad tracks. This
access will serve primarily as a site circulation access to
Parcels B, C, D, E, and F and a service access to Parcel A.
The number of vehicles utilizing this access will be fairly
low (estimate <10% of the generated trips). This access will
have little effect on the operation of any of the other key
intersections analyzed. Consideration should be given to
eliminating this access and providing the main access to
Parcel A with an adequate deceleration lane. This would
emphasize the main access to Parcel A, the retail area. If
this right-in/right-out access is approved, it can be
controlled by the at -grade railroad crossing gates that exist
on Horsetooth Road. Traffic projections indicate the need
for a right -turn auxiliary lane. If the City requires the
auxiliary lane, it should also be controlled by the gates.
This would necessitate constructing a new gate base on the
south side of Horsetooth with longer gate arms.
Accident Analysis
The recommended control devices and geometrics should
minimize vehicular conflicts and maximize vehicle separation.
Therefore, the accident rate should be at its minimum for a
typical urban condition.
10
I V . CONCLUSIONS
This study assessed the impacts of the Timberline-
Horsetooth Property on the short range (1992) and long range
(2010) street system in the vicinity of the proposed
development. As a result of this analysis, the following is
concluded:
- The development of the Timberline-Horsetooth Property
is feasible from a traffic engineering standpoint. At full
development as proposed, approximately 12,500 trip ends will
be generated at this site daily.
- The Horsetooth/Timberline intersection currently
operates acceptably with signal control and the existing
geometrics.
- By 1992, given the first phase of development of the
Timberline-Horsetooth Property; Phase 1 of Collinda.le
Business Park; Phases 1, 2, and S of Fox Meadows; and an
increase in background traffic, the signalized intersection
of Horsetooth/Timberline will operate acceptably with the
existing geometrics and left -turn signal phases. At this
level of development, Timberline Road and Horsetooth Road can
remain two lane streets with auxiliary lanes at the access to
Parcel A. Left -turn exits at the Horsetooth/Access
intersection will operate unacceptably during the afternoon
peak hour. There is little that can be done to improve this.
operation. There will be left -turn storage conflicts between
the Timberline/Horsetooth intersection and the Horsetooth/
Access intersection.
- No new signals are warranted in the short range
future. With full development of the Timberline-Horsetooth
Property and other nearby properties, signals will likely be
warranted at the Timberline/Big Horn and the Horsetooth/
Access intersections.
- Signals at the Timberline/Caribou and Timberline/Big
Horn intersections will not negatively impact the signal
progression along Timberline Road. The signal at the
Horsetooth/Access intersection will not negatively impact the
signal progression along Horsetooth Road. This. intersection
will function as a minor signalized intersection.
- By 2010, the Horsetooth/Timberline intersection will
operate acceptably in the peak hours with geometric
improvements to both Horsetooth Road and Timberline Road.
The necessary geometrics are shown in Figure 10. With
signalization, the Horsetooth/Access and Timberline/Big Horn
intersections will operate acceptably. The proposed right-
in/right-out access_• to Timberline will operate acceptably.
It must be placed at a distance from Horsetooth Road based
it
•
•
upon the design speed of Timberline Road. A right -turn
deceleration lane should be designed at this access. The
proposed right-in/right-out access from Horsetooth Road is
projected to have little effect on traffic generated at this
site. It will primarily serve as a convenience access to the
southern portion of the site. Consideration should be given
to eliminating this access in order to emphasize the main
access to Parcel A.
- With the recommended control and geometrics, the
accident rate should be at an acceptable level for typical
urban conditions.
12
1 N Fr ti A c_...